Coming off an unbeaten homestand of six games, coming to AT&T Park with the same number of wins (35) as the defending World Series champions, the Padres moved ahead of the San Francisco Giants in the National League West Division standings. They took over third place with a 5-3 defeat of the Giants in 13 innings.

Pinch-hitter Andrew Cashner, the scheduled starting pitcher for tonight’s game, bunted for a base hit to score Alexi Amarista with the go-ahead run in the 13th. The Padres added an insurance run when Giants reliever Jake Dunning walked Yasmani Grandal with the bases loaded.

Chase Headley had tied the game in the seventh with his opposite-field single against relief pitcher Jean Machi, who had wild-pitched the Padres’ previous run home immediately after replacing starter Barry Zito an inning earlier. And Padres center fielder Will Venable made a game-saving catch in the bottom of the 12th to send the game to the 13th.

A series-opening win alone bodes well for the Padres, who were swept on their last trip to San Francisco, but swept the Giants back in San Diego. This three-game visit breaks up a stretch of 13 games at Petco Park, where the Padres have been making all sorts of hay in the past month.

Monday night, though, you couldn’t tell your players without a disabled list. Which still may be where both hamstrung shortstop Everth Cabrera and sore-shouldered Carlos Quentin are also headed.

Strikingly, of the nine Padres starters, the only two who were in the Opening Day lineup were Chris Denorfia and pitcher Edinson Volquez. Headley and Logan Forsythe were then on the disabled list, Yasmani Grandal on suspension and left fielder Kyle Blanks was in Triple-A Tucson. Pedro Ciriaco, the utility player who started against the Giants at shortstop, wasn’t even with the Padres’ organization before last week.

Seventy games in, Cabrera finally missed his first start of the year. Cabrera and Quentin indeed are now in a state of limbo, given time for their injuries to improve before a call is made about the DL.

“I wish I could be more concrete with this,” said manager Bud Black. “Cabby’s got a mild hamstring strain. We’ll keep an eye on it. Hopefully, we’ll get to a point where we decide whether to put him on the disabled list. Same thing with Q. We’ll give him a day or two and evaluate his status.

“We don’t want to pull the trigger on the disabled list just yet. That’s the safest way to play it. But in both cases, that (DL) is a possibility.”

The Giants were working with a makeshift lineup, too, due to injuries to star third baseman Pablo Sandoval, second baseman Marco Scutaro and outfielder Angel Pagan. MVP catcher Buster Posey took a scheduled off day.

Volquez got pinged to bits by the Giants, who had only six hits off him, with four of the half-dozen singles and a walk accounting for San Francisco’s three-run fourth.